1. Field of the Invention
The present invention relates to a voltage detection circuit, especially to a voltage detection circuit for detecting the voltages of a plurality of battery cells in a battery pack.
2. Description of Related Art
Generally speaking, when recharging a rechargeable battery, a voltage detection circuit will be utilized to monitor the voltage of each of a plurality of battery cells in the rechargeable battery. When an abnormal condition is detected, the voltage detection circuit will stop the recharging procedure to protect the rechargeable battery from damage and thereby prolongs its usage life.
FIG. 1 shows a circuit diagram of a known voltage detection circuit. As shown in FIG. 1, a battery 10 includes a plurality of battery cells 11 connected in series. The voltage detection circuit 20 includes a plurality of subtraction circuit 21. Each subtraction circuit 21 includes a voltage divider 22, a reference voltage generation unit 23 and a subtraction unit 24 while each of the subtraction circuits 21 respectively connects to a positive electrode and a negative electrode of one of the battery cells 11 so as to detect the voltage of it.
However, the aforementioned voltage detection circuit will result in great detection errors due to the non-identical circuits and high costs due to the large amount of circuits.